Papers by Keyword: Polyelectrolyte Multilayer

Abstract: In this paper, Old Corrugated Container (OCC) was used as the raw material for making paper. The layer-by-layer (LBL) assembly process of creating highly structured thin films was adopted to modify the surface of OCC fibres. Poly dimethyldiallylammonium chloride (PDADMAC) and hydroxyethyl cellulose (HEC) have been used to build up polyelectrolyte multilayers on OCC fibres under a certain condition. Zeta potential analyzer was used to monitor the dynamic adsorption of PDADMAC and HEC with different amount on OCC fibers. Strength measurements of the sheets including tensile index and bursting index were also determined, showing a significant improvement in physical strength with the increase of adsorbed layer number. Compared with not being processed sheets, tensile index and bursting index of sheets from treated fibre with polyelectrolyte multilayers were raised by 36.65% and 49.50%, respectively. Furthermore, filtration time analysis of OCC fibre suspension showed that the built up of PDADMAC and HEC on OCC fibres could improve the fiber-fiber joint strength of joints from polymer-treated fibers, which made the filtration time decline from 30 s to 10.6 s. In addition, SEM was introduced to observe the morphology of the PDADMAC/HEC multilayers. The images revealed that the surface of OCC fibres structured a film like plastic, which could be ascribed to the adsorption layer of polyelectrolyte.

Abstract: Optically active films were built up from poly(allylamine hydrochloride) (PAH) and R-(+)--phenylethylamine derivatives of poly(ethylene-alt-maleic acid) (PEMA-PEA) with substituting degrees (DS) ranging from 0.48 to 0.97. The growth of the film was monitored with the circular dichroism (CD) and the UV spectrophotometer and the effect of DS of PEMA-PEA on the film was investigated. UV and CD data show the growth regime of the multilayer changing from exponential to linear. Deposition amounts of PEMA-PEA in multilayer films decrease with the increase in DS of PEMA-PEA, which was explained based on the conformation of the polyelectrolyte and the charge overcompensation as the polyelectrolyte was deposited on the surface of the film. These results are of benefit to the development of multilayer films for the chiral separation of enantiomers.

Abstract: Biological mineralization proceeds within an organic matrix and is induced and controlled by extracellular, highly acidic matrix macromolecules. Our group has recently prepared organic-inorganic nanocomposite coatings by a strategy that closely mimics these processes. The strategy involves depositing a matrix of polyelectrolyte multilayers (PE MLs), alternating with layers of amorphous calcium phosphate (ACP) particles, then "in situ" growing nanosized apatite crystals within that matrix [1, 2]. Here we describe the results of biological "in vitro" and "in vivo" testing of these materials.

Abstract: In the production of artificial bone and tooth implants, coating of the surfaces of hard, but bioinert materials (metals, polymers) with calcium phosphate crystals has been used to improve bioactivity and facilitate osteointegration. Recently low temperature methods, involving precipitation from aqueous solutions (biomimetic precipitation) including coprecipitation of specific organic macromolecules (growth hormones, enzymes, proteins) have been developed. In this paper an alternative approach is presented, which consists in first laying down a matrix consisting of polyelectrolyte multilayers (PE MLs) alternating with layers of amorphous calcium phosphate (ACP) particles and subsequently growing calcium phosphate crystals upon/within the multilayers. This attractive approach leads to the formation of a new class of true organic-inorganic nanocomposite coatings. In a previous communication we have shown preliminary results, which point to the feasibility of this approach [1]. Here we describe in detail the design, synthesis and characteristics of the thus obtained nanocomposite coatings.